ABSTRACT It is an old debate in social science, what is most influential, actors or structures? The paper resumes the discussion by concretely asking, how can the radical policy shift towards West Africa in the wake of the terrorist attacks on the US in September 11, 2001, be explained by applying an agency-structure approach? The article applies a theoretical framework combining neo-classical realist thinking with the reasoning found in historical institutionalism. Concepts like path dependency and critical juncture are helpful. The roles and priorities of the core foreign policy actors in the United States and in the European Union are discussed before the article identifies international and domestic structures that might constrain the role and influence of the relevant foreign policy decision-makers. It is concluded that neither international nor domestic structures represented strong obstacles to the foreign policy decision makers’ ambitions to implement radical policy changes towards West Africa.